Halogenations of 3-aryl-1H-pyrazol-5-amines

  1. Jing He,
  2. Yueting Wei,
  3. Yijiao Feng,
  4. Chuntian Li,
  5. Bin Dai and
  6. Ping LiuORCID Logo

Submitting author affiliation: Shihezi University, Shihezi, China

Beilstein Arch. 2021, 202166. https://doi.org/10.3762/bxiv.2021.66.v1

Published 24 Sep 2021

  • Preprint

Abstract

A direct C-H halogenation of 3-aryl-1H-pyrazol-5-amines with NXS (X = Br, I, Cl) as cheap and safe halogenating reagents at room temperature has been developed. This transformation provides an effective metal-free protocol towards the synthesis of novel 4-halogenated pyrazole derivatives with moderate to excellent yields. The method represents simple and mild reaction conditions, broad substrate scope as well as gram-scale synthesis. The utility of this procedure is established by further transformations of the 4-halogenated products. Mechanism studies show that DMSO plays a dual role of catalyst and solvent.

Keywords: Halogenation; Metal-free; Pyrazol-5-amine; Synthesis; 4-halogenopyrazole

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When a peer-reviewed version of this preprint is available, this information will be updated in the information box above. If no peer-reviewed version is available, please cite this preprint using the following information:

He, J.; Wei, Y.; Feng, Y.; Li, C.; Dai, B.; Liu, P. Beilstein Arch. 2021, 202166. doi:10.3762/bxiv.2021.66.v1

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